Module java.desktop
Package java.awt

Class FlowLayout

  • All Implemented Interfaces:
    LayoutManager, Serializable

    public class FlowLayout
extends Object
implements LayoutManager, Serializable
    A flow layout arranges components in a directional flow, much like lines of text in a paragraph. The flow direction is determined by the container's componentOrientation property and may be one of two values:
    • ComponentOrientation.LEFT_TO_RIGHT
    • ComponentOrientation.RIGHT_TO_LEFT
    Flow layouts are typically used to arrange buttons in a panel. It arranges buttons horizontally until no more buttons fit on the same line. The line alignment is determined by the align property. The possible values are:

    For example, the following picture shows an applet using the flow layout manager (its default layout manager) to position three buttons:

    Graphic of Layout for Three Buttons

    Here is the code for this applet: 

     import java.awt.*;
 import java.applet.Applet;

 public class myButtons extends Applet {
     Button button1, button2, button3;
     public void init() {
         button1 = new Button("Ok");
         button2 = new Button("Open");
         button3 = new Button("Close");
         add(button1);
         add(button2);
         add(button3);
     }
 }

    A flow layout lets each component assume its natural (preferred) size.

    Since:
    1.0
    See Also:
    ComponentOrientation, Serialized Form

    • Field Summary

      Fields 
      Modifier and Type Field Description
      static int CENTER
      This value indicates that each row of components should be centered.
      static int LEADING
      This value indicates that each row of components should be justified to the leading edge of the container's orientation, for example, to the left in left-to-right orientations.
      static int LEFT
      This value indicates that each row of components should be left-justified.
      static int RIGHT
      This value indicates that each row of components should be right-justified.
      static int TRAILING
      This value indicates that each row of components should be justified to the trailing edge of the container's orientation, for example, to the right in left-to-right orientations.

    • Constructor Summary

      Constructors 
      Constructor Description
      FlowLayout​()
      Constructs a new FlowLayout with a centered alignment and a default 5-unit horizontal and vertical gap.
      FlowLayout​(int align)
      Constructs a new FlowLayout with the specified alignment and a default 5-unit horizontal and vertical gap.
      FlowLayout​(int align, int hgap, int vgap)
      Creates a new flow layout manager with the indicated alignment and the indicated horizontal and vertical gaps.

    • Constructor Detail

      • FlowLayout

        public FlowLayout​()
        Constructs a new FlowLayout with a centered alignment and a default 5-unit horizontal and vertical gap.

      • FlowLayout

        public FlowLayout​(int align)
        Constructs a new FlowLayout with the specified alignment and a default 5-unit horizontal and vertical gap. The value of the alignment argument must be one of FlowLayout.LEFT, FlowLayout.RIGHT, FlowLayout.CENTER, FlowLayout.LEADING, or FlowLayout.TRAILING.
        Parameters:
        align - the alignment value

      • FlowLayout

        public FlowLayout​(int align,
                  int hgap,
                  int vgap)
        Creates a new flow layout manager with the indicated alignment and the indicated horizontal and vertical gaps.

        The value of the alignment argument must be one of FlowLayout.LEFT, FlowLayout.RIGHT, FlowLayout.CENTER, FlowLayout.LEADING, or FlowLayout.TRAILING.

        Parameters:
        align - the alignment value
        hgap - the horizontal gap between components and between the components and the borders of the Container
        vgap - the vertical gap between components and between the components and the borders of the Container

    • Method Detail

      • getAlignment

        public int getAlignment​()
        Gets the alignment for this layout. Possible values are FlowLayout.LEFT, FlowLayout.RIGHT, FlowLayout.CENTER, FlowLayout.LEADING, or FlowLayout.TRAILING.
        Returns:
        the alignment value for this layout
        Since:
        1.1
        See Also:
        setAlignment(int)

      • setAlignment

        public void setAlignment​(int align)
        Sets the alignment for this layout. Possible values are
        • FlowLayout.LEFT
        • FlowLayout.RIGHT
        • FlowLayout.CENTER
        • FlowLayout.LEADING
        • FlowLayout.TRAILING
        Parameters:
        align - one of the alignment values shown above
        Since:
        1.1
        See Also:
        getAlignment()

      • getHgap

        public int getHgap​()
        Gets the horizontal gap between components and between the components and the borders of the Container
        Returns:
        the horizontal gap between components and between the components and the borders of the Container
        Since:
        1.1
        See Also:
        setHgap(int)

      • setHgap

        public void setHgap​(int hgap)
        Sets the horizontal gap between components and between the components and the borders of the Container.
        Parameters:
        hgap - the horizontal gap between components and between the components and the borders of the Container
        Since:
        1.1
        See Also:
        getHgap()

      • getVgap

        public int getVgap​()
        Gets the vertical gap between components and between the components and the borders of the Container.
        Returns:
        the vertical gap between components and between the components and the borders of the Container
        Since:
        1.1
        See Also:
        setVgap(int)

      • setVgap

        public void setVgap​(int vgap)
        Sets the vertical gap between components and between the components and the borders of the Container.
        Parameters:
        vgap - the vertical gap between components and between the components and the borders of the Container
        Since:
        1.1
        See Also:
        getVgap()

      • setAlignOnBaseline

        public void setAlignOnBaseline​(boolean alignOnBaseline)
        Sets whether or not components should be vertically aligned along their baseline. Components that do not have a baseline will be centered. The default is false.
        Parameters:
        alignOnBaseline - whether or not components should be vertically aligned on their baseline
        Since:
        1.6

      • getAlignOnBaseline

        public boolean getAlignOnBaseline​()
        Returns true if components are to be vertically aligned along their baseline. The default is false.
        Returns:
        true if components are to be vertically aligned along their baseline
        Since:
        1.6

      • addLayoutComponent

        public void addLayoutComponent​(String name,
                               Component comp)
        Adds the specified component to the layout. Not used by this class.
        Specified by:
        addLayoutComponent in interface LayoutManager
        Parameters:
        name - the name of the component
        comp - the component to be added

      • layoutContainer

        public void layoutContainer​(Container target)
        Lays out the container. This method lets each visible component take its preferred size by reshaping the components in the target container in order to satisfy the alignment of this FlowLayout object.
        Specified by:
        layoutContainer in interface LayoutManager
        Parameters:
        target - the specified component being laid out
        See Also:
        Container, Container.doLayout()

      • toString

        public String toString​()
        Returns a string representation of this FlowLayout object and its values.
        Overrides:
        toString in class Object
        Returns:
        a string representation of this layout